Process for converting cyannaphthalene-sulfonic acids



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PRGCESS FOR CONVERTING CYANNALPHTHALENE-SULFONIC ACIDS.

No Drawing. '0rigina1 application filed February aa- 192?, Serial Ho. M0332, and in Germany may 17,

1926. Divided and this application filed November 10, 1927. Serial No. 232,466. r

This application is a division of our Patent No. 1,677,086, filed February 24th, 1927.

, We have found, that if cyannaphthalenesulfonic acids, containing at least one sulfonic in which formula the group OY stands in ortho or para position to the group Z, the Xs mean hydrogen atoms, of which one or more may be replaced by a monovalent substituent, Y means hydrogen or an alk l residue, Z the groups ON, CONH' and CO H.

The general formula shows the range of substances, obtained according to the conditions applied. By acting with milder acting alkaline'agents, the cyangroup of the employed cyannaphthalene-sulfonic' acids remains unattached and hydroxy-cy'annaphtha-, lone-compounds are formed corresponding to the above formula, Y being hydrogen and Z being CN, by acting with stronger alkaline acting agents the cyangroup is saponified t0 the carboxyamido(Z= CONH in this case) or to the carboxy-grou (Z==COOH in this case) whereas the su fonic group is exchanged by hydrojxyl (OH), when the applied alkaline acting agent is an aqueous caustic alkali, or by an alkoxy-group generally when applying caustic alkalies 1n the resence of an alcohol. This latter reaction, y which an alkoxy-group is introduced into the molecule, is aparticularly remarkable one without any analogy in the naphthalene se-.

ries. In this manner especially alkoxynaphthalenecarboxyamids corresponding to the above formula, Z being CONH and Y being arr-alkyhresidue, and hydroxyand alkoxynaphthoic acids are obtained corresponding to the above formula, Z being COOH and Y being hydrogen or an alkyl residue.

Under the term alkaline acting agents we understand caustic alkalies in the presence of water or of an alcohol, acting either at ordinary pressure or in.a closed vessel at elevated pressure. Under milder acting alkaline agents the following have been found especially suitable: basic alkaline salts such as sodium, formate, acetate, borate, phosphate. Such agents, the caustic alkalies' as Well as the milder acting agents may be used advantageously in the presence of inorganic or organic diluents in order to keep the mass homogeneous and easily liquid, such as para afiine, naphthalene, tertiary aromatic bases I as dimethylaniline or N-alkyl-carbazol, higher fatty acids, glycerine or low melting salts.

The aforesaid reactions take place at remarkably low temperatures, namely at about 80250 6., whereas Boyle and Shedler and.

Butler and Royle (see Journ. of Chem. Soc.

London, vol. 123, pages 1641, 1649) -must apply temperatures above 260300 O. for exchanging the sulfonic group by the hydroxyllene-sulfonic acids.

The starting materials for these reactions,

namely the orthoand para-cyannaphthaproducts.

In order to further illustratev our inven tion the following examples are given.

Ewample 1.

20 parts of the sodium salt of Q-cyannaphthalene-l-sulfonic acid (obtainable from 2- aminonaphthalene-l-sulfonic acid by Sandmeyers reaction) are intimately mixed with about 40 parts of finely powdered caustic potash and about 150 parts of parafiine and the mixture is heated to about 140 C. while stirring. After some time the mass is cooled down, diluted with water and filtered. Upon acidifying the filtrate an evolution of sulfur dioxide occurs and a colorless compound separates out, forming long needles when regroup in the corresponding carboxynaphthaas I ' crystallized from dilute alcohol, melting at iii -l'l9. The new compound combines with diazocompounds, forming azodyestufi's. According to the result of comparative syn thetic and analytic reactions it seems to correspond to the following formula:

0H m l l instead of caustic potash also sodium ace tats or formats with or Without addition of parafiine or another suitable diluent may be used for the reaction. Also heating of the sodium salt oi the cyannaphthalene-sultonic acid by itseli eventually with addition oi? sand or similar acting substances is suficient by forming the cyannaphthoi. This core pound is converted into the corresponding 1 naphthol-Q-carboxyiic acid by treating it With'alkaline saponii ying agents, for in stance heating it with dilute caustic el indies. it the sodium salt of 1-cyannaphthalenee-suli onic acid is treated in the same manner with a milder acting alkaline agent the corresponding si-hydroxyd-cyannaphbhelERS-COHIPOUDIF; is obtained.

Example 2?. 4 parts of caustic potash and 1 part of Water are heated in a suitable vessel until the mass is dissolved. Then 1 part of the sodium salt of E-cyannaphthalene-1-sulfonic acid is added at about 150 C The vessel is closed and then heating is continued under reflux. The temperature is slowly increased While stirring to about 200 220 0;, and the 'mass is kept at this temperature untilthe evolution of ammonia ceases. After coolingv down, the mass is dissolved in water and filtered. Upon acidif ing the 1.2-hydroxynaphthoic acid of the fbrmulazcoon ucts of conversion may be obtained. So for instance by treating 2-cyannaphthalene-3fidisulfonic acid with caustic alkalies according to the conditions applied in this example a new acid is obtained, being probably 3-hydroxy-fi-sulfo-naphthalene 2 carboxlic acid; by carrying out the process under more vigorous conditions particularly at more elevated temperatures, as end product of the reaction 3.6-dihydroxy-naphthalene-2-carboxylic acid is formed.

Ewample 3.

10 parts of caustic potash and 1. part of -Water are heatedcin a suitable vessel until. the mass is dissolved. Then 2 parts of the sodium salt of i-cyannaphthalene-lsulfonic acid are added at about 1609 C. The vessel is closed and then heating is continued under reflux. The temperature of the mass is increased as quickly as pomible to about 200 C. and the mass is kept at this temperature for a short time. After cooling down, it is diluted with Water and almost neutralized. filtered from some impurities and the clear filtrate is acidified by means of hydrochloric acid. l7l ith an evolution oi sulfor dioxide lxl-hydronaphthoic acid oi the formula:

scribed above at about 200 0., the lA-hydroxynaphthoic acid is also formed with an excellent yield in a pure state.

When subjecting in the same manner the nuclear substitution products of lA-cynnaphtholene-sulfonic acid such as the 6- and 7 -sulfoderivatives (obtainable by treating the diazotized 1-naphthylamine-4.6 and -4.7-disu'lfonic acids Dahls acids 11 and III) with cuprous cyani e according to Sandmeyers reaction) to the action of alkaline agents, the

corresponding derivatives of the products of conversion may be obtained.

We claim: g 1. The process which comprises treating with a caustic alkali at a temperature of from about 150 to about 250 C. a cyannanhthalene sulfonic acid of the general formula:

ON s our wherein the'Xs stand for hydrogen atoms of I memes which oneor more may be replaced by a monovalent substituent, and wherein the cyanogen and sulfonic acid groups stand in ortho or para position to each other.

2. The process which comprises heating a compound of the general formula:

wherein Y represents hydrogen or a cyanogen group, one Y being hydrogen and the other Y being a cyanogen group, to a temperature of from about 150 to about 250 C. in the presence of a caustic alkali.

3.. The process which comprises heating in a closed vessel one part of a compound of the 20 general formula:

tures.

RICHARD HERZ. FRITZ SCHULTE. WERNER ZERWEGK. 

